This application claims the priority of German patent document 199 21 449.2, filed May 8, 1999, the disclosure of which is expressly incorporated by reference herein.
The invention relates to a guidance system for assisting a lane changing of a motor vehicle.
A guidance system of this generic type, for assisting a lane change by a motor vehicle from a current lane to an adjacent target lane, is disclosed, for example, in German Patent Document DE 43 13 568 C1. In this system, the forward space and the rearward space of at least the adjacent target lane are monitored for the desired lane change; the spacing between objects detected there (particularly vehicles), and their speeds are measured; and the safety distances are computed therefrom. When all measured distances are larger than the computed safety distances, the possibility of a lane change is recognized. As the result, the driver is largely freed of monitoring tasks and of estimating distances and speeds of vehicles which are following and which are driving ahead. This guiding assistance system is used preferably for passing and merging into an adjacent lane.
German Patent Document DE 195 26 452 C1 discloses a monitoring device which includes an object detection unit for detecting objects in a rearward side space area, and a warning indicating unit which is activated as a function of signals of the object detection unit which coincide with a detected lane change request for emitting a warning signal. The analysis unit determines whether an object is present in a rearward side space section extending beyond the vehicle in the rear, and moving at a higher speed than the vehicle; if so, it activates the warning display for emitting a warning signal when, in addition, it detects a lane change request pertaining to this side range. Lane change requests are preferably detected by way of the flasher position or the steering angle adjustment.
German Patent Document DE 195 07 957 C1 discloses a vehicle with an optical scanning device for a lateral road range. As an optical scanning device, the vehicle contains several infrared transmitting elements arranged side-by-side, an associated CCD-array, and an analysis unit connected on the output side. The analysis unit is equipped for determining contrast and detecting contours. By means of this system, the road surface is scanned to determine a respective road boundary. The travel time determination and the contrast time determination permit the detection of lateral lane markings and the determination of the respective vehicle distance from such markings.
One disadvantage of this type of vehicle guidance assistance system for a lane change from a current lane to an adjacent target line is that, although the vehicle which is following is recognized by means of rearward side space monitoring, the system is incapable of precisely assigning of such vehicle to a driving lane. Particularly in the case of curvy roads a vehicle that follows in the same lane is detected by the rearward side space monitoring system; this leads to an erroneous detection of the vehicle which is following as a lane change obstacle.
It is therefore an object of the invention to provide a vehicle guidance assistance system of the above-mentioned type which achieves more precise and more reliable support of the driver during a lane change.
This and other objects and advantages are achieved by the lane change assistance system according to the invention, which includes an object detection unit for detecting objects in a laterally adjacent rearward space area of the vehicle. An analysis unit receives signals from the object detection unit and determines whether an object is situated in a dead angle section (blind spot) of the monitored rearward side space, or whether any such object in a section of the monitored rearward side space which is beyond a dead angle section, is moving forward at a higher speed than the system vehicle. If so, and if, in addition, it detects at the same time a lane change request pertaining to the corresponding side area, it activates a warning indicating unit for emitting a warning signal. According to the invention, a position detection device is provided which determines path data of the obstacle vehicle and the road geometry data, as well as the position of the system vehicle on the road. When the object detection unit detects an obstacle vehicle which is following in the rearward side space, corresponding to the covered distance recorded by the position detection device and the road geometry, a position assignment of the vehicle which is following is determined relative to the road.
It is an important advantage of the invention that the guidance system for assisting a lane change can precisely determine whether the obstacle vehicle which is following is situated in the target lane. This is particularly advantageous in the case of a multiple-curve route, because a vehicle which is following and is situated in the same lane as the first vehicle but is detected by the rearward side space monitoring device is correctly classified by the guidance system, and therefore no warning device is activated. In this case, a lane change can take place although the rearward side space monitoring device detects the vehicle which is following.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.